Scaling and Area

The area of a circle of radius 1 is $$\pi$$ units squared. Use scaling to explain why the area of a circle of radius $$r$$ is $$\pi r^2$$ units squared.

Trapezoid $$A’B’C’D$$ was created by dilating trapezoid $$ABCD$$ using $$D$$ as the center of dilation. Description: A large trapezoid A'B'C'D' comprised of smaller shapes on a grid. The blue shape ABCD is a smaller trapezoid. Triangle Q in top right corner. Quadrilateral P in lower right corner. How can you see your answer to these questions in the diagram?

Each image shows a quadrilateral in a plane. The quadrilateral has been dilated using a center above the plane and a scale factor between 0 and 1. Estimate the scale factor that was used for each dilation. Dilation A.

Each image shows a quadrilateral in a plane. The quadrilateral has been dilated using a center above the plane and a scale factor between 0 and 1. Estimate the scale factor that was used for each dilation. Dilation B.

Each image shows a quadrilateral in a plane. The quadrilateral has been dilated using a center above the plane and a scale factor between 0 and 1. Estimate the scale factor that was used for each dilation. Dilation C.

Select the solid whose cross sections are dilations of some two-dimensional shape using a point directly above the shape as a center and scale factors ranging from 0 to 1.

What is the total surface area of the triangular prism shown? 

Find the surface area of this figure.

A square pyramid is covered with decorative wrapping paper with no overlap.  The net of the box is shown on the right.  How many square centimeters of wrapping paper are needed to cover the surfaces of the box? 

When finding Surface Area which type of units could be on the end of your answer?